1. Field of the Invention
The present invention relates to a technology for reducing power consumption of an image processing apparatus.
2. Description of the Related Art
With an increasing number of documents being used in offices, an image processing apparatus such as a printer, a copier, and a multifunction peripheral (MFP) is being used frequently. For example, an image formed on an original is read by a scanner, and image data of the image is stored in a computer via a network or is shared between computers in the network. Furthermore, the image data is printed out by transferring the image data to a printer, an MFP, etc.
In recent years, it has become a critical issue to improve efficiency in power usage in the image processing apparatus for the environmental conservation. Furthermore, the power consumption of the image processing apparatus is economically wasteful for a user especially when the image processing apparatus is in a standby mode or if the image processing apparatus cannot be efficiently used.
In conventional technologies, the image processing apparatus has a power saving mode in which the power consumption is reduced such as by stopping or reducing power supply to main components. When a predetermined time period elapses in a standby status, the image processing apparatus shifts to the power saving mode. In the power saving mode, for example, if a sheet is placed on an exposure glass, the image processing apparatus uses it as a trigger and shifts from the power saving mode to a normal mode. Then, necessary power or rated current is supplied to each essential component, thereby enabling usage of the image processing apparatus.
Japanese Patent Application Laid-open No. 2003-156968 discloses an image processing apparatus having a power saving mode. If printing is not performed for a predetermined time, for example, the image processing apparatus stops power supply to a fixing unit and shifts to a low-power-consumption mode. When returning to the normal mode, the temperature of the fixing unit for starting printing is determined based on a print mode for a job that is to be processed first.
In a technology disclosed in Japanese Patent Application Laid-open No. 2006-293212, when a voltage drop occurs during a warm-up in a copy-start enable status, contents of the settings may be initialized. Therefore, when a voltage drop is detected, the image processing apparatus is switched to a low-power operation mode in which the image processing apparatus operates with a power level lower than that in the normal operation mode.
However, the above conventional technologies still need improvement in reducing the power consumption while enhancing the usability of the image processing apparatus. Specifically, the technology disclosed in Japanese Patent Application Laid-open No. 2003-156968 is for shifting the operation mode to the power saving mode and returning back to the normal mode after the power is on and each unit in the image processing apparatus becomes stable. The technology disclosed in Japanese Patent Application Laid-open No. 2006-293212 is for operating the image processing apparatus in the voltage-drop status after the power is on and each unit in the image processing apparatus becomes stable. Therefore, the above conventional technologies do not address reduction of the power consumption in an unstable status immediately after the power is turned on. Typically, the image processing apparatus consumes large power and may cause errors immediately after the power is turned on. Therefore, it is desirable to reduce the power consumption at the time of turning on the image processing apparatus.